diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-02-03 07:40:08 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-02-04 00:23:57 +0300 |
| commit | 38ab52e8e1e2dd65f2d349f82553335813b638d2 (patch) | |
| tree | 659bcbc397163954d2845ef6f438996da8ee1412 /net | |
| parent | 5226b7919641f285bf0f8db84deeb3920b160ec7 (diff) | |
| download | linux-38ab52e8e1e2dd65f2d349f82553335813b638d2.tar.xz | |
tcp: clear pfmemalloc on outgoing skb
Josef Bacik diagnosed following problem :
I was seeing random disconnects while testing NBD over loopback.
This turned out to be because NBD sets pfmemalloc on it's socket,
however the receiving side is a user space application so does not
have pfmemalloc set on its socket. This means that
sk_filter_trim_cap will simply drop this packet, under the
assumption that the other side will simply retransmit. Well we do
retransmit, and then the packet is just dropped again for the same
reason.
It seems the better way to address this problem is to clear pfmemalloc
in the TCP transmit path. pfmemalloc strict control really makes sense
on the receive path.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_output.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 956bea9a5394..ccf1ef4dcba4 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -964,6 +964,13 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, */ skb->ooo_okay = sk_wmem_alloc_get(sk) < SKB_TRUESIZE(1); + /* If we had to use memory reserve to allocate this skb, + * this might cause drops if packet is looped back : + * Other socket might not have SOCK_MEMALLOC. + * Packets not looped back do not care about pfmemalloc. + */ + skb->pfmemalloc = 0; + skb_push(skb, tcp_header_size); skb_reset_transport_header(skb); |